docs: def dump(*args, **kwargs):
      """Dump a numpy.ndarray to file stream.
  
      This works exactly like the usual `json.dump()` function,
      but it uses our custom serializer.
      """
      kwargs.update(dict(cls=NumpyEncoder,
                         sort_keys=True,
                         indent=4,
                         separators=(',', ': ')))
      return _json.dump(*args, **kwargs)